Audio cassettes and other magnetic recording media have conventionally been used indoors and under other mild temperature and humidity conditions. However, recently marketed cassette decks for car stereo sets and cassette tape recorders with a radio are used outdoors and within vehicles under hostile temperature and humidity conditions. Several problems arise when magnetic recording media are used under such hostile conditions: tape squeal, level drop and unwanted tape running. These magnetic recording media discussed above are described in, for example, U.S. Pat. No. 4,135,016.